Code help?

[Beau]

Output:
how many burgers do you want ? 12
ok each burgers cost 1.55 each

I get this error

Error:
Traceback (most recent call last):
  File "main.py", line 6, in <module>
    print("\nso the price of your burger will be £" + str(float(num_burgers * cost_burgers)))
TypeError: can't multiply sequence by non-int of type 'float'
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